Trucks are encased in ice after a warehouse fire in Chicago on Jan. 23, 2013. The large fire occurred as an Arctic blast gripped the U.S. Midwest and Northeast. At least three deaths were linked to the frigid weather, and fierce winds made some locations feel as cold as 50 degrees below zero Fahrenheit.

A huge winter blizzard, called "Nemo" by the media, pummeled the northeastern United States in February. A foot of snow blanketed New York City and 36 inches covered Boston. The storm also left hundreds of thousands of people across the east coast without power and led to the death of at least four people.

China's smog problem gained international media attention when in January air pollution in Beijing and much of northern China soared past healthy levels, reaching up to 40 times higher than the standard set by the World Health Organization.

The smog returned in October, shutting down Harbin, a Chinese city of 11 million people. Smog — caused by industrial pollution, coal, and agricultural burning — doesn't appear because of a sudden increase in air pollutants, but because of certain weather conditions that trap pollutants in the air.

Weeks of heavy rain in central Europe this spring caused rivers to overflow and led to flooding that forced tens of thousands of Germans, Hungarians, and Czechs to leave their homes. In this picture a garden with a swimming pool is inundated by the waters of the Elbe river in the German state of Saxony-Anhalt. The floods were the worst the region had seen in a decade.

In June, early monsoon rains caused India's longest river, the Ganges, to flood. The waters swept away houses, left tens of thousands stranded, and killed more than 100 people. The statue of a Hindu deity is submerged by flood waters of the Ganges in Uttarakhand, India.

A house sits undamaged in the aftermath of the Black Forest Fire in Black Forest, Colorado on June 13, 2013. Firefighters struggled to contain the blaze that raged for a week near Colorado Springs. It was the most destructive wildfire on record in Colorado history. The cause of the fire — whether it was intentional or not — is still under investigation.

A historic heat wave gripped most of the western United States in early July, sending dozens to hospitals and shattering temperature records for this time of year in places like Death Valley and Las Vegas.

The extreme July heat also fueled a forest fire in central Arizona that killed 19 firefighters. It was the third-deadliest single-wildfire incident ever recorded in the U.S., according to the National Interagency Fire Center, and the deadliest for the state.

In October, Typhoon Wipha was dubbed a "once-in-a-decade" typhoon that threatened Tokyo, but fortunately weakened as it came ashore. The typhoon killed more than a dozen people in Japan, most on an offshore island, but largely spared the capital.

Floodwaters caused by unusually heavy rains ravaged a Connecticut-size area of Colorado in September, killing at least seven people, destroying thousands of homes, and blocking hundreds of roads and bridges. In aerial photo a tractor sits partially submerged in a farm field after flooding along the South Platte River.

Mount Sinabung on the Indonesian island of Sumatra spews hot gas and rock several miles in the air in mid-November. The mountains rumblings have been growing stronger since September, when it started erupting for the first time since 2010.

An aerial view shows the path of destruction caused by a tornado that touched down in Washington, Illinois on Nov. 18, 2013. A fast-moving storm system triggered multiple tornadoes that killed at least six people as it tore across the Midwest.

In September, visitors took pictures of tidal waves created by a severe typhoon in Hangzhou, in the Zhejiang province of China. The storm killed two people in the Philippines and injured nine people in Taiwan.

A photographer took pictures of Italy's Mount Etna, Europe's tallest and most active volcano, spewing lava as it erupted on the southern island of Sicily on Nov. 17, 2013. It was the sixteenth time that Etna has erupted in 2013.

Photographer and volcanologist Tom Pfeiffer captured a perfectly-shaped steam ring from Mt. Etna. According to National Geographic: "The air in the center moves faster than the air at the edge, which causes the aerial donut to spin and allows it to maintain its shape."

An aerial view of houses devastated by Typhoon Haiyan, the biggest storm ever to make landfall, is seen on Nov. 25, 2013. Typhoon Haiyan struck the central Visayan islands in the Philippines on Nov. 8, killing more than 5,200 people, displacing 4.4 million, and destroying 12 billion pesos ($274 million) in crops, property, and infrastructure.

Visitors to the Grand Canyon were treated to a rare event the day after Thanksgiving when the entire canyon filled with fog due to what's known as "temperature inversion." Warm air sits on top of cooler air and prevents layers of the atmosphere from mixing. It happened on a cloudless day, creating a particularly beautiful view, something that only happens once every 10 years, a ranger said.